805  
FNUS74 KMOB 131024  
FWSMOB  
 
SPOT FORECAST FOR DESOTO 8566...USDA FOREST SERVICE  
NATIONAL WEATHER SERVICE MOBILE AL  
524 AM CDT THU AUG 13 2020  
 
FORECAST IS BASED ON IGNITION TIME OF 0600 CDT ON AUGUST 13.  
IF CONDITIONS BECOME UNREPRESENTATIVE...CONTACT THE NATIONAL WEATHER  
SERVICE.  
   
DISCUSSION
 
SCATTERED TO NUMEROUS SHOWERS AND STORMS WILL AFFECT  
THE BURN SITE, MAINLY DURING THE AFTERNOON. AFTERNOON RELATIVE  
HUMIDITIES REMAIN ABOVE CRITICAL LEVELS. TRANSPORT WINDS WILL BE  
INITIALLY LIGHT WESTERLY THEN SWITCH TO THE SOUTHWEST THIS AFTERNOON.  
A LIGHT WEST TRANSPORT WIND RETURNS LATE TONIGHT THEN SWITCHES TO  
THE SOUTHWEST LATE FRIDAY AFTERNOON. DISPERSION VALUES WILL BE FAIR  
TODAY AND FAIR/GENERALLY GOOD ON FRIDAY. HEAT INDEX VALUES OF 100-102  
ARE EXPECTED FROM NOON THROUGH 5 PM.  
 
FOG POTENTIAL AND OTHER REMARKS...PATCHY FOG IS POSSIBLE DURING THE  
LATE NIGHT AND EARLY MORNING HOURS WITH VISIBILITIES OF 3 TO 5 MILES.  
   
TODAY
 
 
SKY/WEATHER.........PARTLY SUNNY (55-65 PERCENT). CHANCE OF SHOWERS  
AND THUNDERSTORMS IN THE MORNING. SHOWERS AND  
THUNDERSTORMS LIKELY IN THE AFTERNOON.  
CHANCE OF PCPN......60 PERCENT.  
LAL.................NO TSTMS UNTIL 0700, THEN 9-15 STRIKES UNTIL  
1300, THEN 16-25 STRIKES.  
MAX TEMPERATURE.....AROUND 91.  
MIN HUMIDITY........60 PERCENT.  
WIND (20 FT)........LIGHT WINDS. GUSTY AND ERRATIC WINDS EXPECTED  
NEAR THUNDERSTORMS.  
MIXING HEIGHT.......6200 FT AGL.  
MIXING HEIGHT (M)...61-1890 METERS AGL.  
TRANSPORT WINDS.....EAST AROUND 1 MPH SHIFTING TO THE NORTH EARLY  
IN THE MORNING, THEN SHIFTING TO THE SOUTHWEST  
2 TO 7 MPH IN THE LATE MORNING AND AFTERNOON.  
TRANSPORT WINDS M/S.EAST AROUND 0 METERS/SECOND SHIFTING TO THE  
NORTH EARLY IN THE MORNING, THEN SHIFTING TO  
THE SOUTHWEST 1 TO 3 METERS/SECOND IN THE LATE  
MORNING AND AFTERNOON.  
DISPERSION INDEX....4 INCREASING TO 20.  
LVORI...............6.  
STABILITY CLASS.....2.  
 
TIME (CDT) 6 AM 8 AM 10 AM NOON 2 PM 4 PM  
SKY (%).........35 32 38 48 69 83  
WEATHER COV..... CHANCE CHANCE CHANCE LIKELY LIKELY  
WEATHER TYPE....NONE RNSHWR RNSHWR RNSHWR RNSHWR RNSHWR  
TSTM COV........ CHANCE CHANCE CHANCE LIKELY LIKELY  
CHC OF PCPN (%).10 30 40 40 60 60  
LAL.............1 3 3 3 4 4  
TEMP............75 78 85 90 90 88  
RH..............97 91 75 62 62 66  
20 FT WIND DIR..NNE NNE N WSW SSW S  
20 FT WIND SPD..0 2 3 4 5 5  
20 FT WIND GUST.1 5 8 10 10  
MIX HGT (FT)....200 1300 3600 5400 5100 2800  
MIX HGT (M).....60 400 1100 1650 1550 850  
TRANSP WIND DIR.E N W SSW SSW SW  
TRANSP WIND SPD.1 1 3 5 6 7  
TRANS WIND DIR..E N W SSW SSW SW  
TRANS SPD (M/S).0 0 1 2 3 3  
DISPERSION IDX..1 3 14 24 18 16  
LVORI...........9 6 4 3 2 3  
   
TONIGHT
 
 
SKY/WEATHER.........MOSTLY CLOUDY (60-70 PERCENT) THEN BECOMING  
PARTLY CLOUDY (35-45 PERCENT). SHOWERS AND  
THUNDERSTORMS LIKELY EARLY IN THE EVENING, THEN  
CHANCE OF SHOWERS AND THUNDERSTORMS EARLY IN  
THE EVENING. SLIGHT CHANCE OF SHOWERS AND  
THUNDERSTORMS IN THE LATE EVENING AND  
OVERNIGHT.  
CHANCE OF PCPN......60 PERCENT.  
LAL.................16-25 STRIKES UNTIL 1900, THEN 9-15 STRIKES  
UNTIL 2200, THEN 1-8 STRIKES UNTIL 0400, THEN  
9-15 STRIKES.  
MIN TEMPERATURE.....AROUND 74.  
MAX HUMIDITY........97 PERCENT.  
WIND (20 FT)........LIGHT WINDS. GUSTY AND ERRATIC WINDS EXPECTED  
NEAR THUNDERSTORMS.  
MIXING HEIGHT.......300 FT AGL.  
MIXING HEIGHT (M)...91-853 METERS AGL.  
TRANSPORT WINDS.....WEST 5 TO 9 MPH.  
TRANSPORT WINDS M/S.WEST 2 TO 4 METERS/SECOND.  
DISPERSION INDEX....17 DECREASING TO 5.  
LVORI...............6.  
STABILITY CLASS.....4.  
 
TIME (CDT) 6 PM 8 PM 10 PM MIDNGT 2 AM 4 AM  
SKY (%).........80 76 72 52 42 41  
WEATHER COV.....LIKELY CHANCE S CHC S CHC S CHC S CHC  
WEATHER TYPE....RNSHWR RNSHWR RNSHWR RNSHWR RNSHWR RNSHWR  
TSTM COV........LIKELY CHANCE S CHC S CHC S CHC S CHC  
CHC OF PCPN (%).60 30 20 20 20 20  
LAL.............4 3 2 2 2 3  
TEMP............85 81 78 77 75 75  
RH..............72 82 91 90 97 97  
20 FT WIND DIR..SSW SSW SW S SSW WNW  
20 FT WIND SPD..4 3 1 1 1 1  
20 FT WIND GUST.7 6 2 2 2 2  
MIX HGT (FT)....2800 700 700 500 400 300  
MIX HGT (M).....850 210 210 150 120 90  
TRANSP WIND DIR.SW SSW SSW SW WSW WNW  
TRANSP WIND SPD.7 9 9 8 6 5  
TRANS WIND DIR..SW SSW SSW SW WSW WNW  
TRANS SPD (M/S).3 4 4 4 3 2  
DISPERSION IDX..17 5 4 4 3 3  
LVORI...........3 5 6 7 7 8  
   
FRIDAY
 
 
SKY/WEATHER.........PARTLY SUNNY (55-65 PERCENT). SLIGHT CHANCE OF  
SHOWERS AND THUNDERSTORMS EARLY IN THE MORNING,  
THEN CHANCE OF SHOWERS AND THUNDERSTORMS IN THE  
MORNING. SHOWERS AND THUNDERSTORMS LIKELY IN  
THE AFTERNOON.  
CHANCE OF PCPN......70 PERCENT.  
LAL.................9-15 STRIKES UNTIL 1300, THEN 16-25 STRIKES.  
MAX TEMPERATURE.....AROUND 91.  
MIN HUMIDITY........58 PERCENT.  
WIND (20 FT)........LIGHT WINDS. GUSTY AND ERRATIC WINDS EXPECTED  
NEAR THUNDERSTORMS.  
MIXING HEIGHT.......5600 FT AGL.  
MIXING HEIGHT (M)...122-1707 METERS AGL.  
TRANSPORT WINDS.....SOUTHWEST 5 TO 9 MPH.  
TRANSPORT WINDS M/S.SOUTHWEST 2 TO 4 METERS/SECOND.  
DISPERSION INDEX....7 INCREASING TO 33.  
LVORI...............5.  
STABILITY CLASS.....2.  
 
TIME (CDT) 6 AM 8 AM 10 AM NOON 2 PM 4 PM  
SKY (%).........42 46 53 62 70 77  
WEATHER COV.....S CHC CHANCE CHANCE CHANCE LIKELY LIKELY  
WEATHER TYPE....RNSHWR RNSHWR RNSHWR RNSHWR RNSHWR RNSHWR  
TSTM COV........S CHC CHANCE CHANCE CHANCE LIKELY LIKELY  
CHC OF PCPN (%).20 50 50 50 70 70  
LAL.............3 3 3 3 4 4  
TEMP............75 78 85 90 91 88  
RH..............97 91 75 62 58 66  
20 FT WIND DIR..W W W WSW WSW SW  
20 FT WIND SPD..1 2 3 5 6 5  
20 FT WIND GUST.2 5 7 10 10 10  
MIX HGT (FT)....400 1300 3200 4800 4900 3400  
MIX HGT (M).....120 400 980 1460 1490 1040  
TRANSP WIND DIR.W W W W W WSW  
TRANSP WIND SPD.5 6 9 9 9 9  
TRANS WIND DIR..W W W W W WSW  
TRANS SPD (M/S).2 3 4 4 4 4  
DISPERSION IDX..3 11 32 35 31 29  
LVORI...........9 5 3 2 1 3  
 

 
FORECASTER...29  
REQUESTED BY...MARK JAMIESON  
TYPE OF REQUEST...PRESCRIBED  
.TAG 2010808.0/MOB  
.DELDT 08/13/20  
.FORMATTERVERSION 1.0.26  
.EMAIL MARK.JAMIESON@USDA.GOV  
 
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